Grinding wheel and holder therefor



March 6, 1928. 1,661,861 F. J. TONE: f

GRINDING WHEEL AND HOLDER THEREFOR Filed June 23, 1925 -2 sheets-sheet 1 INVENTOR rMarch s, 192s. 1,661,861 F. J. TONE lGRINDING WHEEL AND HOLDER THEREFOR Filed June 23. 1925 2 Sheets-Sheet 2 NVENTOR Mge@ Patented Mar. 6,1928." i

UNITED STATES 1,661,861 PATENT OFFICE.

FRANK J. TONE, F NIAGARA FALLS, NEW YORK, ASSIG-NOR T0 THE CARBORUNDUM COMPANY, OF NIAGARA FALIJS, NEW YORK, A CORPORATION OF PENNSYLVANIA @BINDING WHEEL AND HOLDER THEREFOR.

i Application led June 23, 1925. Serial No. 39,104.

For grinding certain classes of work, such as the inside surfaces of bath tubs to prepare them for enameling, and similar castings, for examplefthe rinding wheel is mounted onthe end of a exible operating shaft, yin order to enable the operator to move the wheel from point to point, and both the face and the edge of the grinding wheel are used as grinding surfaces. This work is very l0 hard on the grinding wheel and causes it to wear away rapidly, necessitating frequent replacement of wheels. Heretofore such wheels have been formed cup-shaped and the operating shaft extended through the bo'ttom of the cup and the wheel secured 'l thereto by means of a nut engaging the threaded end of lthe shaft inside the hollow cup. With this method of mounting it was impossible to wear ldown the wheel lower than the nut, so that the'stub to be thrown away constituted a considerable portion of the wheel. Also, there wasV considerable danger to the operator by reason ofthe liability of the rapidly rotating wheel cracking and then flying to ieces, asthis method of'mounting did not a ord any support for Y the cracked wheel tending to prevent itV from fl ing to pieces.

By tlsie present invention I have rovided 3Q an improved form of grinding w eel and mounting therefor designed to overcome Vthe above objectionablefeatures inherent in the e old method of mounting grinding wheels of this character.

The invention is illustrated in the accompanying drawings, wherein:

Fi re 1 is a side elevation of one form of f'grin ing wheel and holder mounted on the end of a flexible operating shaft` and ein $0. bodying myinvention;

Figure 2 is a sectional viewl ofthe ing wheel and holder;

Figure 3 is an inverted plan view, partly broken away, of theg'rinding wheel; 45,. Figure 4 is a plan ,view of the holder;

Fi re 5 is sectional view of another form of grinding wheel and holder embodying my invention;

Figure 6 is an inverted plan view, partly `broken away, of the grinding wheel shown in Fi 5 Fiilrrd 7 is a Figure -8 is a holder. f Referring to the embodiment of the 1nplan view'of the holder; and detail sectional view ofthe grind-..1

vention shown in Figures 1 to 4, inclusive', the grinding wheel 2 has a central bore 3 and a reduced hub portion 4 projecting from one end face thereof. The hub portion 4 has a plurality of uniformly spaced lugs 5 projecting radially from its outer periphery, these lugs having undercut curved outer surfaces 6- which are eccentric with respect to the axis of the wheel, thereby providing cam surfaces.

The holder comprises a' plate 7 having a central hole to receive the screw-threaded end 8 of the operating shaft 9, the plate being adapted to be clamped between an enlarged portion l() of the shaft andl a nut 11 mounted on the screw-threaded end 8. TheV plate 10 has a plurality of integral lugs 12 projecting upwardly therefrom at the peripheral edge of the plate and corresponding in number to the number of lugs 5 on the hub of. the grinding wheel. The lugs 12 have undercut inner curved edges which are eccentricto the axis of theplate 7 and are adapted to engage the undercut curved surfaces 6 of the lugs 5.

In applying. the beider 'to the wheel, the

lugs 12 are inserted through the spaces between the lugs 5 of the grinding wheel and then the wheel and the holder are relatively rotated to cause the eccentric undercut inner surfaces of the lugs 12 to frictionally engage v,thev undercut outer surfaces of the lugs 5;

tion 4 to hold the wheel against turning in.

its holder.

In the form of the invention illustrated in Figures 5 to 8, inclusive, the hub portion 4** of the wheel 2a is provided with spaced lugs 5 having-undercut curved outer surfaces 6EL which are concentric with the axis of the wheel.

The plate 7 a in this form of the invention has lugs 12a, the inner undercut edges of which are concentric with axis of the plate. Adjacent one end of each lug is a pin 14, these pins being provided to limit relative rotation between the wheel and plate when the lugs l2a areslipped through the spaces between the lugs 5 and the wheel and plate relatively rotated to bring the lugs 5* and 19.x1 into cooperative relation. When the holder has been applied to the wheel in this manner, the set screws 13 are set up to hold the wheel against relative rotation in the holder.

It will be noted that in both forms of the invention the holder engages the reduced hubportion only of the wheel, thereby permitting the wheel to be worn down almost, if not quite, to said hub portion, which constitutes only a relatively small portion of the wheel. Moreover, the hub'is at least partially surrounded by the holder, so that the holder will tend to hold the wheel together in case it cracks in service an'd thereby lessen the danger of the wheel exploding. Moreover, I make no claim broadly to these features, as they constitute the invention of Hobart C. Beach and are claimed in his copending application Serial No. 39,011 tiled of even date herewith.

I claim:

' 1. A grinding wheel assembly including an abrasive Wheel formed of bonded abrasive grains having an integral hub portion of reduced diameter thereon, a series of lu disposed around the periphery of the hub portion, the peripheral surface of each lug bein undercut, each lug also being outwar' y curved from one end toward the other, and a metal holder secured to the an abrasive wheel formed of bonded abrasive grains having an integralhub portion of reduced diameter thereon, a series of lugs disposed around the periphery of the hub portion, the peripheral surface of each lug bein undercut, each lug also ,being outwar ly curved from one end toward the other, and a ,metal holder secured to the hub portion having a central portion with a series of undercut 1u on the face thereof corresponding to' the u on the said hub portion of the wheel, sai lugs on the holder eing adapted to embrace and intert with the lugs of the said hub portion and to be forced into wedging relation therewith, and adjustable means on the holder for pressing against the end of said reduced hub portion of the wheel to increase the frictional engagement between the said cooperating lugs.

In testimony whereof I have hereunto set my hand.

FRANK J. TONE. 

